/*
 * Copyright 2001-2005 The Apache Software Foundation Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License. You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language governing permissions and limitations under the
 * License.
 */
package org.apache.commons.net.nntp;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

import org.apache.commons.io.input.CountingInputStream;
import org.apache.commons.net.MalformedServerReplyException;
import org.apache.commons.net.ProtocolCommandListener;
import org.apache.commons.net.ProtocolCommandSupport;
import org.apache.commons.net.SocketClient;

/***********************************************************************************************************************
 * The NNTP class is not meant to be used by itself and is provided only so that you may easily implement your own NNTP
 * client if you so desire. If you have no need to perform your own implementation, you should use
 * {@link org.apache.commons.net.nntp.NNTPClient}. The NNTP class is made public to provide access to various NNTP
 * constants and to make it easier for adventurous programmers (or those with special needs) to interact with the NNTP
 * protocol and implement their own clients. A set of methods with names corresponding to the NNTP command names are
 * provided to facilitate this interaction.
 * <p>
 * You should keep in mind that the NNTP server may choose to prematurely close a connection if the client has been idle
 * for longer than a given time period or if the server is being shutdown by the operator or some other reason. The NNTP
 * class will detect a premature NNTP server connection closing when it receives a
 * {@link org.apache.commons.net.nntp.NNTPReply#SERVICE_DISCONTINUED NNTPReply.SERVICE_DISCONTINUED } response to a
 * command. When that occurs, the NNTP class method encountering that reply will throw an
 * {@link org.apache.commons.net.nntp.NNTPConnectionClosedException} . <code>NNTPConectionClosedException</code> is a
 * subclass of <code> IOException </code> and therefore need not be caught separately, but if you are going to catch it
 * separately, its catch block must appear before the more general <code> IOException </code> catch block. When you
 * encounter an {@link org.apache.commons.net.nntp.NNTPConnectionClosedException} , you must disconnect the connection
 * with {@link #disconnect  disconnect() } to properly clean up the system resources used by NNTP. Before disconnecting,
 * you may check the last reply code and text with {@link #getReplyCode  getReplyCode } and
 * {@link #getReplyString  getReplyString }.
 * <p>
 * Rather than list it separately for each method, we mention here that every method communicating with the server and
 * throwing an IOException can also throw a {@link org.apache.commons.net.MalformedServerReplyException} , which is a
 * subclass of IOException. A MalformedServerReplyException will be thrown when the reply received from the server
 * deviates enough from the protocol specification that it cannot be interpreted in a useful manner despite attempts to
 * be as lenient as possible.
 * <p>
 * <p>
 * @author Daniel F. Savarese
 * @author Rory Winston
 * @author Ted Wise
 * @see NNTPClient
 * @see NNTPConnectionClosedException
 * @see org.apache.commons.net.MalformedServerReplyException
 **********************************************************************************************************************/

public class NNTP extends SocketClient {
    /** * The default NNTP port. Its value is 119 according to RFC 977. ** */
    public static final int DEFAULT_PORT = 119;
    // We have to ensure that the protocol communication is in ASCII
    // but we use ISO-8859-1 just in case 8-bit characters cross
    // the wire.
    // private static final String DEFAULT_ENCODING = "ISO-8859-1";
    // public static final String DEFAULT_ENCODING = "UTF-8";
    public static final String DEFAULT_ENCODING = "ISO-8859-1";
    private StringBuffer __commandBuffer;
    protected String lastCommand;
    protected CountingInputStream countingInputStream;
    /**
     * Wraps {@link SocketClient#_input_} to communicate with server. Initialized by {@link #_connectAction_}. All
     * server reads should be done through this variable.
     */
    protected BufferedReader _reader_;
    // TODO change this to non-bufferedreader to avoid wrapping multiple BufferedReaders within tasks
    /**
     * Wraps {@link SocketClient#_output_} to communicate with server. Initialized by {@link #_connectAction_}. All
     * server reads should be done through this variable.
     */
    protected BufferedWriter _writer_;
    /*******************************************************************************************************************
     * A ProtocolCommandSupport object used to manage the registering of ProtocolCommandListeners and te firing of
     * ProtocolCommandEvents.
     ******************************************************************************************************************/
    protected ProtocolCommandSupport _commandSupport_;

    boolean _isAllowedToPost;
    int _replyCode;

    String _replyString;

    /*******************************************************************************************************************
     * The default NNTP constructor. Sets the default port to <code>DEFAULT_PORT</code> and initializes internal data
     * structures for saving NNTP reply information.
     ******************************************************************************************************************/
    public NNTP() {
        setDefaultPort(DEFAULT_PORT);
        __commandBuffer = new StringBuffer();
        _replyString = null;
        _reader_ = null;
        _writer_ = null;
        _isAllowedToPost = false;
        _commandSupport_ = new ProtocolCommandSupport(this);
    }

    /*******************************************************************************************************************
     * Adds a ProtocolCommandListener. Delegates this task to {@link #_commandSupport_  _commandSupport_ }.
     * <p>
     * @param listener The ProtocolCommandListener to add.
     ******************************************************************************************************************/
    public void addProtocolCommandListener(ProtocolCommandListener listener) {
        _commandSupport_.addProtocolCommandListener(listener);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP ARTICLE command to the server, receive the initial reply, and return the
     * reply code.
     * <p>
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int article() throws IOException {
        return sendCommand(NNTPCommand.ARTICLE);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP ARTICLE command to the server, receive the initial reply, and return the
     * reply code.
     * <p>
     * @param articleNumber The number of the article to request from the currently selected newsgroup.
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int article(int articleNumber) throws IOException {
        return sendCommand(NNTPCommand.ARTICLE, Integer.toString(articleNumber));
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP ARTICLE command to the server, receive the initial reply, and return the
     * reply code.
     * <p>
     * @param messageId The message identifier of the requested article, including the encapsulating &lt and &gt
     * characters.
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int article(String messageId) throws IOException {
        return sendCommand(NNTPCommand.ARTICLE, messageId);
    }

    /*******************************************************************************************************************
     * A convenience method to send the AUTHINFO PASS command to the server, receive the reply, and return the reply
     * code. If this step is required, it should immediately follow the AUTHINFO USER command (See RFC 2980)
     * <p>
     * @param password a valid password.
     * @return The reply code received from the server. The server should return a 281 or 502 for this command.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int authinfoPass(String password) throws IOException {
        String passParameter = "PASS " + password;
        return sendCommand(NNTPCommand.AUTHINFO, passParameter);
    }

    /*******************************************************************************************************************
     * A convenience method to send the AUTHINFO USER command to the server, receive the reply, and return the reply
     * code. (See RFC 2980)
     * <p>
     * @param username A valid username.
     * @return The reply code received from the server. The server should return a 381 or 281 for this command.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int authinfoUser(String username) throws IOException {
        String userParameter = "USER " + username;
        return sendCommand(NNTPCommand.AUTHINFO, userParameter);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP BODY command to the server, receive the initial reply, and return the reply
     * code.
     * <p>
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int body() throws IOException {
        return sendCommand(NNTPCommand.BODY);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP BODY command to the server, receive the initial reply, and return the reply
     * code.
     * <p>
     * @param articleNumber The number of the article to request from the currently selected newsgroup.
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int body(int articleNumber) throws IOException {
        return sendCommand(NNTPCommand.BODY, Integer.toString(articleNumber));
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP BODY command to the server, receive the initial reply, and return the reply
     * code.
     * <p>
     * @param messageId The message identifier of the requested article, including the encapsulating &lt and &gt
     * characters.
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int body(String messageId) throws IOException {
        return sendCommand(NNTPCommand.BODY, messageId);
    }

    /*******************************************************************************************************************
     * Closes the connection to the NNTP server and sets to null some internal data so that the memory may be reclaimed
     * by the garbage collector. The reply text and code information from the last command is voided so that the memory
     * it used may be reclaimed.
     * <p>
     * @exception IOException If an error occurs while disconnecting.
     ******************************************************************************************************************/
    @Override public void disconnect() throws IOException {
        super.disconnect();
        countingInputStream = null;
        _reader_ = null;
        _writer_ = null;
        _replyString = null;
        _isAllowedToPost = false;
    }

    /*******************************************************************************************************************
     * Fetches a reply from the NNTP server and returns the integer reply code. After calling this method, the actual
     * reply text can be accessed from {@link #getReplyString  getReplyString }. Only use this method if you are
     * implementing your own NNTP client or if you need to fetch a secondary response from the NNTP server.
     * <p>
     * @return The integer value of the reply code of the fetched NNTP reply. in response to the command.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while receiving the server reply.
     ******************************************************************************************************************/
    public int getReply() throws IOException {
        __getReply();
        return _replyCode;
    }

    /*******************************************************************************************************************
     * Returns the integer value of the reply code of the last NNTP reply. You will usually only use this method after
     * you connect to the NNTP server to check that the connection was successful since <code> connect </code> is of
     * type void.
     * <p>
     * @return The integer value of the reply code of the last NNTP reply.
     ******************************************************************************************************************/
    public int getReplyCode() {
        return _replyCode;
    }

    /*******************************************************************************************************************
     * Returns the entire text of the last NNTP server response exactly as it was received, not including the end of
     * line marker.
     * <p>
     * @return The entire text from the last NNTP response as a String.
     ******************************************************************************************************************/
    public String getReplyString() {
        return _replyString;
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP GROUP command to the server, receive the reply, and return the reply code.
     * <p>
     * @param newsgroup The name of the newsgroup to select.
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int group(String newsgroup) throws IOException {
        return sendCommand(NNTPCommand.GROUP, newsgroup);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP HEAD command to the server, receive the initial reply, and return the reply
     * code.
     * <p>
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int head() throws IOException {
        return sendCommand(NNTPCommand.HEAD);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP HEAD command to the server, receive the initial reply, and return the reply
     * code.
     * <p>
     * @param articleNumber The number of the article to request from the currently selected newsgroup.
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int head(int articleNumber) throws IOException {
        return sendCommand(NNTPCommand.HEAD, Integer.toString(articleNumber));
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP HEAD command to the server, receive the initial reply, and return the reply
     * code.
     * <p>
     * @param messageId The message identifier of the requested article, including the encapsulating &lt and &gt
     * characters.
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int head(String messageId) throws IOException {
        return sendCommand(NNTPCommand.HEAD, messageId);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP HELP command to the server, receive the reply, and return the reply code.
     * <p>
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int help() throws IOException {
        return sendCommand(NNTPCommand.HELP);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP IHAVE command to the server, receive the reply, and return the reply code.
     * <p>
     * @param messageId The article identifier, including the encapsulating &lt and &gt characters.
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int ihave(String messageId) throws IOException {
        return sendCommand(NNTPCommand.IHAVE, messageId);
    }

    /*******************************************************************************************************************
     * Indicates whether or not the client is allowed to post articles to the server it is currently connected to.
     * <p>
     * @return True if the client can post articles to the server, false otherwise.
     ******************************************************************************************************************/
    public boolean isAllowedToPost() {
        return _isAllowedToPost;
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP LAST command to the server, receive the reply, and return the reply code.
     * <p>
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int last() throws IOException {
        return sendCommand(NNTPCommand.LAST);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP LIST command to the server, receive the reply, and return the reply code.
     * <p>
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int list() throws IOException {
        return sendCommand(NNTPCommand.LIST);
    }

    /**
     * A convenience wrapper for the extended LIST command that takes an argument, allowing us to selectively list
     * multiple groups.
     * <p>
     * @param wildmat A wildmat (pseudo-regex) pattern. See RFC 2980 for details.
     * @return the reply code received from the server.
     * @throws IOException
     */
    public int listActive(String wildmat) throws IOException {
        StringBuffer command = new StringBuffer("ACTIVE ");
        command.append(wildmat);
        return sendCommand(NNTPCommand.LIST, command.toString());
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP NEWGROUPS command to the server, receive the reply, and return the reply
     * code.
     * <p>
     * @param date The date after which to check for new groups. Date format is YYMMDD
     * @param time The time after which to check for new groups. Time format is HHMMSS using a 24-hour clock.
     * @param GMT True if the time is in GMT, false if local server time.
     * @param distributions Comma-separated distribution list to check for new groups. Set to null if no distributions.
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int newgroups(String date, String time, boolean GMT, String distributions) throws IOException {
        StringBuffer buffer = new StringBuffer();

        buffer.append(date);
        buffer.append(' ');
        buffer.append(time);

        if(GMT){
            buffer.append(' ');
            buffer.append("GMT");
        }

        if(distributions != null){
            buffer.append(" <");
            buffer.append(distributions);
            buffer.append('>');
        }

        return sendCommand(NNTPCommand.NEWGROUPS, buffer.toString());
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP NEWGROUPS command to the server, receive the reply, and return the reply
     * code.
     * <p>
     * @param newsgroups A comma-separated list of newsgroups to check for new news.
     * @param date The date after which to check for new news. Date format is YYMMDD
     * @param time The time after which to check for new news. Time format is HHMMSS using a 24-hour clock.
     * @param GMT True if the time is in GMT, false if local server time.
     * @param distributions Comma-separated distribution list to check for new news. Set to null if no distributions.
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int newnews(String newsgroups, String date, String time, boolean GMT, String distributions) throws IOException {
        StringBuffer buffer = new StringBuffer();

        buffer.append(newsgroups);
        buffer.append(' ');
        buffer.append(date);
        buffer.append(' ');
        buffer.append(time);

        if(GMT){
            buffer.append(' ');
            buffer.append("GMT");
        }

        if(distributions != null){
            buffer.append(" <");
            buffer.append(distributions);
            buffer.append('>');
        }

        return sendCommand(NNTPCommand.NEWNEWS, buffer.toString());
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP NEXT command to the server, receive the reply, and return the reply code.
     * <p>
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int next() throws IOException {
        return sendCommand(NNTPCommand.NEXT);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP POST command to the server, receive the reply, and return the reply code.
     * <p>
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int post() throws IOException {
        return sendCommand(NNTPCommand.POST);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP QUIT command to the server, receive the reply, and return the reply code.
     * <p>
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int quit() throws IOException {
        return sendCommand(NNTPCommand.QUIT);
    }

    /*******************************************************************************************************************
     * Removes a ProtocolCommandListener. Delegates this task to {@link #_commandSupport_  _commandSupport_ }.
     * <p>
     * @param listener The ProtocolCommandListener to remove.
     ******************************************************************************************************************/
    public void removeProtocolCommandListener(ProtocolCommandListener listener) {
        _commandSupport_.removeProtocolCommandListener(listener);
    }

    /*******************************************************************************************************************
     * Sends an NNTP command with no arguments to the server, waits for a reply and returns the numerical response code.
     * After invocation, for more detailed information, the actual reply text can be accessed by calling
     * {@link #getReplyString  getReplyString }.
     * <p>
     * @param command The NNTPCommand constant corresponding to the NNTP command to send.
     * @return The integer value of the NNTP reply code returned by the server in response to the command. in response
     * to the command.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int sendCommand(int command) throws IOException {
        return sendCommand(command, null);
    }

    /*******************************************************************************************************************
     * Sends an NNTP command to the server, waits for a reply and returns the numerical response code. After invocation,
     * for more detailed information, the actual reply text can be accessed by calling
     * {@link #getReplyString  getReplyString }.
     * <p>
     * @param command The NNTPCommand constant corresponding to the NNTP command to send.
     * @param args The arguments to the NNTP command. If this parameter is set to null, then the command is sent with no
     * argument.
     * @return The integer value of the NNTP reply code returned by the server in response to the command. in response
     * to the command.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int sendCommand(int command, String args) throws IOException {
        return sendCommand(NNTPCommand._commands[command], args);
    }

    /*******************************************************************************************************************
     * Sends an NNTP command with no arguments to the server, waits for a reply and returns the numerical response code.
     * After invocation, for more detailed information, the actual reply text can be accessed by calling
     * {@link #getReplyString  getReplyString }.
     * <p>
     * @param command The text representation of the NNTP command to send.
     * @return The integer value of the NNTP reply code returned by the server in response to the command. in response
     * to the command.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int sendCommand(String command) throws IOException {
        return sendCommand(command, null);
    }

    /*******************************************************************************************************************
     * Sends an NNTP command to the server, waits for a reply and returns the numerical response code. After invocation,
     * for more detailed information, the actual reply text can be accessed by calling
     * {@link #getReplyString  getReplyString }.
     * <p>
     * @param command The text representation of the NNTP command to send.
     * @param args The arguments to the NNTP command. If this parameter is set to null, then the command is sent with no
     * argument.
     * @return The integer value of the NNTP reply code returned by the server in response to the command.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int sendCommand(String command, String args) throws IOException {
        String message;

        __commandBuffer.setLength(0);
        __commandBuffer.append(command);

        if(args != null){
            __commandBuffer.append(' ');
            __commandBuffer.append(args);
        }
        __commandBuffer.append(SocketClient.NETASCII_EOL);

        _writer_.write(message = __commandBuffer.toString());
        _writer_.flush();

        if(_commandSupport_.getListenerCount() > 0){
            _commandSupport_.fireCommandSent(command, message);
        }

        __getReply();
        lastCommand = __commandBuffer.toString();
        return _replyCode;
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP STAT command to the server, receive the initial reply, and return the reply
     * code.
     * <p>
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int stat() throws IOException {
        return sendCommand(NNTPCommand.STAT);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP STAT command to the server, receive the initial reply, and return the reply
     * code.
     * <p>
     * @param articleNumber The number of the article to request from the currently selected newsgroup.
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int stat(int articleNumber) throws IOException {
        return sendCommand(NNTPCommand.STAT, Integer.toString(articleNumber));
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP STAT command to the server, receive the initial reply, and return the reply
     * code.
     * <p>
     * @param messageId The message identifier of the requested article, including the encapsulating &lt and &gt
     * characters.
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int stat(String messageId) throws IOException {
        return sendCommand(NNTPCommand.STAT, messageId);
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP XHDR command to the server, receive the reply, and return the reply code.
     * <p>
     * @param header a String naming a header line (e.g., "subject"). See RFC-1036 for a list of valid header lines.
     * @param selectedArticles a String representation of the range of article headers required. This may be an article
     * number, or a range of article numbers in the form "XXXX-YYYY", where XXXX and YYYY are valid article numbers in
     * the current group. It also may be of the form "XXX-", meaning "return XXX and all following articles" In this
     * revision, the last format is not possible (yet).
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int xhdr(String header, String selectedArticles) throws IOException {
        StringBuffer command = new StringBuffer(header);
        command.append(" ");
        command.append(selectedArticles);
        return sendCommand(NNTPCommand.XHDR, command.toString());
    }

    /*******************************************************************************************************************
     * A convenience method to send the NNTP XOVER command to the server, receive the reply, and return the reply code.
     * <p>
     * @param selectedArticles a String representation of the range of article headers required. This may be an article
     * number, or a range of article numbers in the form "XXXX-YYYY", where XXXX and YYYY are valid article numbers in
     * the current group. It also may be of the form "XXX-", meaning "return XXX and all following articles" In this
     * revision, the last format is not possible (yet).
     * @return The reply code received from the server.
     * @exception NNTPConnectionClosedException If the NNTP server prematurely closes the connection as a result of the
     * client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be
     * caught either as an IOException or independently as itself.
     * @exception IOException If an I/O error occurs while either sending the command or receiving the server reply.
     ******************************************************************************************************************/
    public int xover(String selectedArticles) throws IOException {
        return sendCommand(NNTPCommand.XOVER, selectedArticles);
    }

    private void __getReply() throws IOException {
        _replyString = _reader_.readLine();

        if(_replyString == null){
            throw new NNTPConnectionClosedException("Connection closed without indication.");
        }

        // In case we run into an anomaly we don't want fatal index exceptions
        // to be thrown.
        if(_replyString.length() < 3){
            throw new MalformedServerReplyException("Truncated server reply: " + _replyString);
        }
        try{
            _replyCode = Integer.parseInt(_replyString.substring(0, 3));
        }
        catch(NumberFormatException e){
            throw new MalformedServerReplyException("Could not parse response code.\nServer Reply: " + _replyString);
        }

        if(_commandSupport_.getListenerCount() > 0){
            _commandSupport_.fireReplyReceived(_replyCode, _replyString + SocketClient.NETASCII_EOL);
        }

        if(_replyCode == NNTPReply.SERVICE_DISCONTINUED){
            throw new NNTPConnectionClosedException("NNTP response 400 received.  Server closed connection.");
        }
    }

    /*******************************************************************************************************************
     * Initiates control connections and gets initial reply, connectdetermining if the client is allowed to post to the
     * server. Initializes {@link #_reader_} and {@link #_writer_} to wrap {@link SocketClient#_input_} and
     * {@link SocketClient#_output_}.
     ******************************************************************************************************************/
    @Override protected void _connectAction_() throws IOException {
        super._connectAction_();
        countingInputStream = new CountingInputStream(_input_);
        _reader_ = new BufferedReader(new InputStreamReader(_input_, DEFAULT_ENCODING));
        _writer_ = new BufferedWriter(new OutputStreamWriter(_output_, DEFAULT_ENCODING));
        __getReply();

        _isAllowedToPost = _replyCode == NNTPReply.SERVER_READY_POSTING_ALLOWED;
    }
}

/*
 * Emacs configuration Local variables: ** mode: java ** c-basic-offset: 4 ** indent-tabs-mode: nil ** End: **
 */
